Surgical scalpel with retractable guard

ABSTRACT

A safety scalpel blade assembly adapted for attachment to a handle ( 12 ), the assembly comprising a scalpel blade ( 10 ) and guard ( 11 ) which extends at least about the cutting edge of the blade ( 10 ), the guard ( 11 ) having attachment means to lock the blade to the guard as the assembly is being attached to the handle and which releases the blade from the guard when the blade is attached to the blade carrier on the handle. Improvements include a removable safety tab ( 60 ) on the guard ( 11 ), means ( 68,71 ) to prevent the blade guard ( 11 ) lifting relative to the handle ( 12 ), a safely catch ( 75 ) to prevent excessive retraction of the guard ( 11 ) and location means ( 80,82 ) to locate the guard ( 11 ) in the extended and retracted positions.

FIELD OF THE INVENTION

This invention relates to various improvements to a surgical scalpelwhich has a retractable guard to reduce the incidence of sharps injury.

The invention will be described with reference to a surgical scalpel butit should be appreciated that the invention can be construed broadlyenough to cover any other type of cutting implement which requires safehandling procedures.

BACKGROUND ART

Surgical scalpels or surgical knives which are in commercial use have ahandle and a disposable blade. The blade can be detached from the handleand disposed of by deposit in a special container which can thereafterbe handled with reduced hazard of sharps injury.

A sharps injury means any cutting or penetrating object that can bereasonably anticipated to penetrate the skin or other part of the bodyto result in an exposure incident which includes occupational exposureto blood and other potentially infectious materials. Clearly, thiscovers scalpels and other types of surgical knives.

The commercially available scalpels which have a disposable bladegenerally have reusable handles. The handle can be sterilised byautoclaving and reused, and these handles are usually formed from metal.

The surgical blade comes packaged in a protective foil. The foil iscarefully opened to expose the blade. The blade is then held betweenthumb and finger and carefully attached to an extending projection offinger on the handle. Upon completion of the surgical procedure, theblade is either manually detached from the handle and placed in a sharpsbin, or the handle with the blade is inserted into a container whichbreaks off the blade.

It can be seen that attachment of the blade to the handle is a hazardousprocedure and can easily result in a sharps injury. If the blade ismanually detached, this can also result in a sharps injury which is evenmore hazardous as the blade may be contaminated.

During surgical use, the scalpels can accidentally cut the surgeon'sfingers, or the fingers of nurses and other support persons in theoperating theatre. As well, operating personnel can be accidentally cutwhen the scalpel is passed between personnel.

To partially mitigate against accidental sharps injuries in handling thescalpel, it is known to provide a retractable blade guard. The bladeguard is attached to the handle, and can be manually pushed between anextended blade guarding position, and a retracted blade exposed positionThus, blade guards attached to scalpel handles are known.

These blade guards have some disadvantages. Firstly, by being part ofthe handle, the handle must be thoroughly cleaned from any blood andtissue after use, if the handle is to be reused. The blade guard cancatch and contain tissue, congealed blood, and the like in the variousnooks and cavities in the blade guard and it is extremely difficult toensure that the blade guard is absolutely spotlessly clean to allow thehandle with the attached blade guard to be reused. To allow the handleto be reused many times, the blade guard must be fairly robust and thiscan result in the guard being of fairly complex manufacture, quitebulky, and quite expensive.

A second disadvantage with this arrangement is that the blade guardcannot protect against initial attachment of the sterile blade to thehandle. That is, the blade guard must be fully retracted to expose theprojection or finger on the handle to which the blade is attached. Theblade must be attached in the usual manner which is to initially removeit from its protective foil and then physically attach it to the handle.Thus, existing blade guards do not reduce or eliminate sharps injurieswhich can result in initial attachment of the blade. As well, theseguards do not protect against removal of the blade from the handle.

Our earlier international patent application WO 01/05312 described asurgical scalpel with a retractable guard. The device overcame many ofthe above-mentioned disadvantages.

However, attachment of the blade to the handle could still risk a sharpsinjury especially if the person attaching the blade was inattentive orvery junior.

With larger blades and handles there was the possibility that the guardcould “pop off” the handle when retracted due to some flexibility in thelarger guard.

It was also possible to pull the guard back too far and to pull theguard off the handle.

When the guard was retracted to expose the blade and extended to coverthe blade, there was the possibility of insufficient retraction andextension which could cause a portion of the blade to be exposed [withinsufficient extension] or only partial exposure of the blade cuttingedge [with insufficient retraction]. It was also possible for the guardto inadvertently move during use. Thus a visual check was needed.However there would be an advantage if the fully retracted position andthe fully extended position could be sensed without constant visualchecking, and/or if these positions could be lightly “locked” in place.

OBJECT OF THE INVENTION

The present invention is directed to improvements with respect to asurgical scalpel with a retractable guard, and particularly toimprovements in respect of the device described in our earlierinternational patent application.

The present invention is directed to improvements to a guard assemblywhich contains a blade attached to a blade guard. The assembly can bepackaged within a sterile foil (similar to conventional blades). Theassembly can be removed from the foil and can be safely handled withlittle risk of the blade cutting the person, and the assembly can beattached to a scalpel handle with the blade guard in place.

When the assembly is attached to the scalpel handle, the blade guard canbe retracted fully or partially to expose the blade. When the surgicalprocedure is finished, the blade guard can be pushed back over the bladeand the blade and blade guard can be removed from the handle for safedisposal. In this arrangement, the handle itself does not keep the bladeguard as the guard is disposed with the blade after use.

With this arrangement, there is reduced likelihood of sharps injuries inattachment of a blade to the handle. As well, the handle does not keepthe guard which means that the handle can be more easily cleaned andsterilized for reuse. The guard can stay with the blade when the bladeis removed which reduces the incidence of sharps injury when removingthe blade from the handle.

In one form, the invention resides in a means to improve the method ofattachment of the blade assembly to a handle.

In this form, the invention comprises the provision of a removable tabon the blade assembly which can be removed after the blade has beenattached to the handle and prior to exposing the blade by retracting theguard.

Thus, one form of this invention comprises a safety scalpel bladeassembly adapted for attachment to a handle of the type which has ablade carrier in the form of a finger, the assembly comprising a scalpelblade which can be of conventional manufacture, the scalpel blade havinga slot to allow the blade to be attached to the blade carrier on thehandle, and a guard which extends at least about the cutting edge of theblade, the guard having attachment means to lock the blade to the guardas the assembly is being attached to the handle and which releases theblade from the guard when the blade is attached to the blade carrier onthe handle, and a removable tab on the guard having a portion which canbe gripped by a person.

Suitably, the removable tab has a head portion and a tail portion. Thehead portion suitably extends forwardly of the blade assembly. The tailportion suitably extends at least partially into a slot which is presentin the guard.

Suitably, the removable tab is attached to the guard via at least onebreakable portion. Suitably, a plurality of breakable portions areprovided. These breakable portions are preferably on the tail portion ofthe removable tab.

Suitably, the breakable portions comprise a first breakable portion (afirst neck) and a second breakable portion (a second neck). It ispreferred that the first breakable portion is closer to the head portionof the removable tab and can break more easily than the second breakableportion. Thus, the first breakable portion may be sized for immediatebreakage. The second breakable portion may be more difficult to breakand may require both a twisting action and a leveraged action againstthe underside of the blade to break to ensure that the head of thesafety tab has moved sufficiently away from the blade exposure to besafely operated by hand.

Thus the function of the tab can be to initially prevent retraction ofthe guard and exposure of the blade, until the tab is removed afterwhich the guard can be retracted and the blade exposed. Thus the tabprovides an improvement to the invention by preventing inadvertent orpremature exposure of the blade.

The head portion of the removable tab can either be gripped by a personor may be placed against a solid surface and pushed, both optionsallowing the tab to be removed and allowing the guard to be attached tothe handle with a reduced likelihood of being cut by the blade.

In another form the invention resides in an improvement to a surgicalscalpel with a retractable guard and which contains a blade assembly,the blade assembly comprising a blade and a blade guard, the improvementcomprising means to reduce the ability of the blade guard from liftingrelative to the handle.

This improvement overcomes a disadvantage with earlier devices andespecially earlier devices which comprise a larger handle and arelatively large guard. The disadvantage was that is the guard had adegree of flexibility and could inadvertently be removed from the handlethereby presenting a sharps hazard situation.

In one form, the means can comprise an engagement means on the handleand which engages the guard. The engagement means may comprise anelongated rib or rail in the handle, and a corresponding groove or slotin the guard (or vice versa) such that the guard can slide between theforward and the retracted position but is held against being lifted bythe engagement of the rib or rail in the groove or slot. Of course,other means to prevent the guard from being lifted relative to thehandle are envisaged.

Another means to prevent the guard from being inadvertently removed maycomprise a means to prevent the guard from being retracted too farthereby creating the possibility that the guard can be pushed out ofengagement with the handle.

In one form, this means may comprise an engagement means such as asafety catch which prevents excessive retraction of the guard. Thesafety catch may be provided on the guard can preferably on a forwardportion of the guard. The safety catch may comprise a peg or similartype of member.

Another improvement to the scalpel with retractable guard comprises ameans to positively locate the guard in the extended position and theretracted position. The means may comprise at least one projection whichcan releasably engage in at least one recess when the guard is in theextended position and the retracted position. The arrangement may besuch that an audible “click” is heard when the guard is in the extendedposition or the retracted position, or that a tactile response is felt.

In each improvement, the scalpel blade assembly may be of the typedescribed in our earlier international patent application and maycomprise a scalpel blade assembly comprising a scalpel blade, a guardwhich extends at least about the cutting edge of the blade, andreleasable attachment means to releasably attach the blade to the guard,the attachment means being operable between a locking position where theblade is held relative to the guard such that the cutting edge isprotected by the guard, and a free position where the blade can slideout of the guard.

In a more particularised form, the safety scalpel blade assembly whichis able to be attached to a handle of the type comprises a blade carrierin the form of a finger, the assembly comprising a scalpel blade whichcan be of conventional manufacture and which has a slot which allows theblade to be attached to the blade carrier on the handle, and a guardwhich extends at least about the cutting edge of the blade, the guardhaving attachment means which locks the blade to the guard as theassembly is being attached to the handle thereby preventing the bladefrom cutting a person, but which releases the blade from the guard whenthe blade is attached to the blade carrier on the handle.

In another form, the invention resides in improvements to a scalpelcomprising a scalpel blade assembly and a handle, the scalpel bladeassembly having: a scalpel blade, a guard which extends at least aboutthe cutting edge of the blade, and releasable attachment means toreleasably attach the blade to the guard, the attachment means beingoperable between a locking position where the blade is held relative tothe guard such that the cutting edge is protected by the guard, and afree position where the blade can slide out of the guard, the handlehaving:

a portion which is releasably lockable to the blade, the handle furtherhaving guide means which engages with the guard when the handle isattached to the blade to allow the guard to slide along the guide meanson the handle between a retracted position where at least a portion ofthe cutting edge of the blade is exposed, and an extended position wherethe cutting edge of the blade is protected,

the scalpel further having means to move the attachment means to itsfree position when the handle is attached to the blade, and at least oneimprovement as described above.

The scalpel blade assembly has the scalpel blade initially attached to ablade guard. The assembly can be packed in a sterile foil and the foilcan be opened to safely remove the blade and the blade guard. Theassembly can then be attached to a scalpel handle and thereafter theguard can be retracted to-expose the scalpel blade.

The scalpel blade can be of various types depending on the surgicalprocedure to be carried out. It is usual for the blade to be elongateand to have a forward cutting edge. The blade body is provided with anelongate slot extending therethrough and the slot allows the blade to beattached to a projection or finger on the handle. This arrangement isentirely conventional. The invention is envisaged to cover surgicaldevices which may be other than a blade but which also are attachable toa handle and which require safe handling procedures.

The guard extends at least about the cutting edge of the blade toprotect against sharps injury. The guard may be formed from plasticsmaterial although other materials are envisaged. As the blade assemblyis disposed of after use, it is preferred that the guard is made offairly inexpensive material which is however still suited for use andwhich can be sterilised.

The guard can extend substantially around the blade to form a shroud orsleeve. The forward end of the guard (that is the end where the front ofthe blade sits) should be open or have a passageway to allow the bladeto extend from the guard. To facilitate attachment of the blade/guardassembly to the handle, the guard may be required to have an opening orslot to allow the handle to be attached to the blade while the guard isstill in place, and to allow the guard to be retracted from the bladewhen the blade is attached to the handle.

The assembly has a releasable attachment means. The releasableattachment means functions to initially attach the blade to the guardsuch that when the blade/guard assembly is removed from its protectivepackage, the blade does not inadvertently fall out of the guard orexpose a cutting edge. The attachment means can also function to holdthe blade in the guard when the blade is removed for disposal. In oneform, this can be achieved by a projection or button on the guard whichextends into the slot in the blade body (the slot being where the handleattaches to the blade).

The projection or button therefore prevents the blade from inadvertentlysliding out of the guard and presenting a cutting edge.

If desired, the guard may be provided with a further projection, or finwhich extends into the slot in the blade and can function to prevent theblade from “rattling” in the guard.

The releasable attachment means may also be slightly biased, inter aliato push the blade against a wall of the guard again to prevent the bladefrom rattling or exhibiting undesired movement in the guard.

The blade assembly can be attached to a scalpel or knife handle. Theknife handle can have a forward projection or finger which has a profileto allow it to releasably lock to the slot in the blade. Thisarrangement is known in the art. The handle can be provided with meansto release the blade from the guard when the handle is attached to theblade. In one form, the projection or finger on the handle can have aprofile such that when it attaches to the blade, it also releases theblade from the guard thereby allowing the guard to be retracted toexpose the blade.

The handle is provided with guide means to engage with the guard and toallow the guard to slide between retracted and extended positions. Theguide means can be in the form of a recess in the handle in which theguide slides.

The guard can be retracted from the blade to expose various lengths ofthe blade. For instance, means may be provided to allow the guard to bereleasably locked or held in various retracted positions to exposevarious lengths of the blade. This allows the cutting depth of the bladeto be adjusted, and can also ensure that only a necessary amount ofblade is exposed with the remainder of the blade still being protectedby the guard, the purpose being to further minimise accidental injury.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described with reference to thefollowing figures in which

FIG. 1 is an exploded view of a known scalpel showing the scalpel blade,the blade guard, and the scalpel handle.

FIG. 2 shows the known scalpel blade assembly with the blade initiallyheld within the guard.

FIG. 3 shows the known blade attached to the handle with the guard inthe retracted position exposing the blade.

FIG. 4 is an enlarged view of the known blade guard illustrated in FIG.1.

FIGS. 5A-5C show top, bottom and section views of a known blade guardaccording to an alternative embodiment.

FIGS. 6A-6B illustrates a known blade guard.

FIGS. 7A-7G illustrates a known guard according to a second embodiment.

FIG. 8. Illustrates a scalpel having a blade assembly attached andshowing a safety tab which comprises an improvement.

FIG. 9. Illustrates the safety tab in greater detail.

FIG. 10. Illustrates a top view of the scalpel of FIG. 8.

FIG. 11. Illustrates a side view of the scalpel of FIG. 8.

FIG. 12. Illustrates the safety tab being removed from the guard.

FIG. 13. Illustrates the safety tab being removed from the guard.

FIG. 14. Illustrates a top view of the scalpel having the safety tabbeing removed from the guard.

FIG. 15. Illustrates the safety tab completely removed.

FIG. 16. Illustrates a further improvement which comprises a handleprovided with engagement means to prevent the guard from being liftedout of the recess in the handle.

FIG. 17. Illustrates the handle of FIG. 16 with the guard attached.

FIG. 18. Illustrates a section view of the guard.

FIG. 19. Illustrates a section view of the handle in the recessed areaof the handle.

FIG. 20. Illustrates a front view of the guard according to thisimprovement.

FIG. 21. Illustrates a rear view of the guard of FIG. 20

FIG. 22. Illustrates the front portion of the scalpel showing anengagement means to prevent over retraction of the guard according to afurther improvement.

FIG. 23. Illustrates the scalpel of FIG. 22 with the guard next to thescalpel.

FIG. 24. Illustrates the scalpel of FIG. 23 in greater detail.

FIG. 25. Illustrates a side view of the scalpel containing the guard.

FIG. 26. Illustrates a section view of the front part of a scalpelaccording to another improvement which is directed to allowing the guardto “click” into the forward position and the rear position.

FIG. 27. Illustrates a top view of the scalpel of FIG. 26.

FIG. 28. Illustrates a side view of the scalpel of FIG. 26.

FIG. 29. Illustrates a perspective view of the scalpel of FIG. 26.

FIG. 30. Illustrates a modified guard attached to a handle.

FIG. 31. Illustrates the guard of FIG. 30 from the other side.

FIGS. 32-37 Illustrate the attachment and removal of the retractableguard assembly to a scalpel handle.

BEST MODE

Referring to FIGS. 1 and 7, there are illustrated two versions of aknown scalpel which consist of three main components being a scalpelblade 10, a blade guard 11, and a scalpel handle 12. Blade 10 is ofconventional design and is widely available in the marketplace. Theblade is formed of stainless steel, has a forward cutting edge, and isprovided with an elongate profile slot 13 which is again entirelyconventional. Handle 12 has a forwardly extending projection or finger14 which is profile and has opposed side recesses or grooves 15 (onlyone groove illustrated). Blade 10 is attached to finger 14 with theinternal edges of slot 13 sliding along grooves 15. This is againconventional in the art.

FIG. 1 illustrates guard 11 which functions to cover or protect thecutting edge of blade 10 as the blade is attached. That is, blade 10 canbe attached with guard 11 in place such that at no stage does a person'shand contact the cutting edge of the blade as the blade is attached tofinger 14.

FIGS. 2 and 8 illustrate two versions of a scalpel blade assembly whichconsist of blade 10 and guard 11 with blade 10 now being entirely withinguard 11. Guard 11 in FIGS. 2 and 8 is the same as guard 11 in FIGS. 1and 7 except FIGS. 2 and 8 are inverted views of the guard of FIGS. 1and 7.

Guard 11 can be formed from relatively inexpensive plastic material andis preferably clear or at least translucent such that that the blade canbe seen through the guard. The guard substantially encompasses the bladeto form a shroud or sleeve. The front 16 of the guard is open such thatthe guard can be retracted to expose blade 10. One side wall of guard 11is provided with an elongate slot 17 which extends entirely along theside wall from the front 16 to the rear wall 18 of the guard. Thefunction of slot 17 is to not interfere with retraction of the guardwhen blade 10 is attached to finger 14.

Guard 11 has a releasable attachment means which functions to hold blade10 in guard 11 (see FIGS. 2 and 8) before the blade/guard assembly isattached to scalpel handle 12. In the embodiment of FIG. 2, thereleasable attachment means is in the form of a projection or button 19which is also illustrated in FIG. 5C. Button 19 sits at one end of aflat finger 20 (see FIG. 1). Finger 20 is integrally formed with theremainder of guard 11 and is able to be depressed by virtue of itsfinger-like quality.

A protective raised wall 21 extends around finger 20 but finger 20 isnot attached to wall 21 which means that finger 20 can pivot or bedepressed within the confines of wall 21. Wall 21 functions inter aliato protect the rather small finger against unintentional movement, ordamage.

In the embodiment of FIGS. 7 and 8, the raised wall is not present. Theprojection 50 (see also FIG. 12) has a ramped wall 51 extending fromfinger 20.

In use, the scalpel blade assembly as illustrated in FIGS. 2 and 8 isassembled and can be placed in a foil package in a manner similar tocurrent scalpel blades. The assembly can be removed from a foil packageand it can be seen from FIGS. 2 and 8 that button 19,50 holds the bladewithin guard 11 and therefore the assembly can be picked up by guard 11which means that there is little or no likelihood of the blade causing astick injury.

The assembly can then be placed onto finger 14 with finger 14 passinginto slot 13 to attach the blade to finger 14. Finger 14 is profile suchthat when it extends into slot 13, it also pushes away button 19, 50against the bias of finger 20. This in turn releases blade 1 0 from itshousing 11. For as long as blade 1 0 is attached to finger 14, theprofile of finger 14 keeps button 19,50 out of slot 13 and thereforeprevents button 19,50 from reengaging with the blade. Upon removal ofthe blade and guard assembly, the guard is first pushed to the forwardposition where it covers the blade and then the blade is decoupled fromfinger 14. As soon as this occurs, button 19, 50 is released and withthe bias of finger 20 will re-enter into slot 13 to again hold the bladewithin the guard. The blade and guard assembly can now be safelydisposed of in a sharps bin with little or no likelihood of stick injuryresulting.

Finger 20 is biased to bias button 19, 50 into slot 13. In FIG. 2,button 19 extends from a larger shoulder portion 22 (more clearlyillustrated in FIGS. 5B and 5C). Shoulder portion 22 is too large toextend through slot 13 but instead abuts against one side of the blade.With the biasing action of finger 20, shoulder portion 22 functions togently push the blade against one side wall of guard 11 and prevents theblade from rattling or from exhibiting unintentional movement. Theposition of button 19 is such that when blade 10 is within guard 11 (seeFIG. 2), the button is adjacent the rearpportion of slot 13. Thisprevents the blade from further extension out of the guard.

Movement of the blade in the other direction is prevented as rear end 18of guard 11 does not have an open end as does the front 16. Thus, blade10 is essentially trapped within housing 11 until such time as theassembly is attached to finger 14 which in turn pushes button 19 out ofengagement with slot 13. In FIGS. 8, 12 and 13, button 50 has opposedshoulder portions 52 which serve the same function as shoulder portion22 in FIG. 2.

Handle 12 has a guide means 23 which in the embodiment is in the form ofa recess 24 on the forward portion of handle 12 and immediately behindfinger 14. The recess is sufficiently long such that guard 11 can bepulled back to fully expose blade 10. This fully retracted bladeexposing position is illustrated in FIGS. 3 and 9. The recess 24, whichforms part of the guide means in handle 12, is configured to accept theshape of guard 11.

Recess 24 has opposed side walls 25 which guide the opposed side walls26 of guard 11.

Guard 11 has a number of small projections or buttons 27 extending fromeach side wall 26, and the side walls 25 of recess 24 have correspondingrecesses 28. The function of buttons 27 and recesses 28 is to allow theguard 11 to be retracted along recess 24 and be releasably locked intopreset positions where an opposed pair of buttons 27 click into anopposed pair of recesses 28. The releasable locking arrangement is suchthat the surgeon's thumb is able to slide the guard to release the guardfrom engagement with the guide means. However, when the surgeon's thumbis not on guard 11, the guard is held in place sufficiently to preventit from inadvertently becoming loose. This arrangement has the advantagethat if only a small part of the cutting blade is required, the guardcan be clicked into an only partially retracted position thereby stillprotecting the remainder of the cutting edge of the blade against stickinjury. The guard can also provide a means to measure the depth of thecut by exposing only a certain length of the cutting blade.

The guard has a thumb engageable projection 30 such that a surgeon cangrip the guard by projection 30 and can extend or retract the guard in asingle simple motion. Raised wall 21 prevents the surgeon's thumb fromaccidentally pushing in finger 20.

FIGS. 5A-5C and FIGS. 11-13 show variations to the guard.

In these variations, the guard has an additional fin 31 which sits inslot 13 of blade 10 and functions to keep the blade central. Fin 31 isalso attached to finger 20 such that it is pushed out of the way whenthe blade is attached to the scalpel handle.

FIGS. 6A and 6B illustrate a blade guard 35 which is injection mouldedand consists of two halves 36, 37 connected via a hinge line 38. Theguard is moulded in a flat configuration illustrated in FIG. 6A. Theblade 39 (see FIG. 6B) is placed on one half 37 and the other half 36 isbent via hinge line 38 to overlie the first half 37. The halves are snaplocked together by projections 40 on one of the halves which engage intorecesses 41 on the other half.

Referring now to FIGS. 8-15 there is illustrated a first improvement tothe known type of scalpel blade assembly described above. This firstimprovement is directed to an improvement to the method of attachment ofthe blade assembly to the handle with reduced likelihood of a sharpsincident. In the particular embodiment the improvement comprises aremovable tab 60 which comprises a head portion 61 and a tail portion62. Head portion 61 comprises a flat member which can be gripped betweena person's fingers or which can be pushed against a hard surface. Tailportion 62 is integrally formed with head portion 61 and is positionedto at least partially fill slot 17 in guard 11. The slot 17 isillustrated in FIG. 2.

Tail portion 62 is attached to the remainder of guard 11 by a pluralityof breakaway portions. In the particular embodiment, two sets ofbreakaway portions are provided which comprise a first breakable portion(a first neck 63), and a second breakable portion (a second neck 64).Each breakable portion comprises a pair of thin portions which can betorn away.

Referring to FIG. 12, the first neck 63 comprises a very thin portionwhich can be immediately broken away. Second neck 64 comprises thickerportions which are not as easily broken away. Thus, initial lifting ofhead portion 61 will break neck 63 to allow head portion 61 to be quiteeasily moved away from the rest of guard 11. After that, the tab must betwisted and pulled harder against the underside of blade 10 to allowneck 63 to be broken thereby allowing the tab to be removed entirelyfrom guard 11. This ensures that the tab head 61 has moved sufficientlybelow with the line of the blade exposure to allow it to be safelyoperated by hand. Further pulling of the tab rearwardly will result inguard 11 being retracted to expose blade 10. Thus, the guard can beinitially retracted as the safety tab is removed.

FIG. 15 shows the tab 60 completely removed from guard 11 and shows howguard 11 has been partially retracted to expose blade 10 in a very safemanner.

Another improvement to the scalpel is illustrated in FIGS. 16-21.Briefly, this improvement prevents the guard from lifting out of thehandle. The improvement requires modification to the guard andmodification to the handle. Referring to FIGS. 16-21, there isillustrated a modified handle 65. Handle 65 is provided with a recess66. The recess has a side wall 67. Side wall 67 is provided with alongitudinal rib 68 which is best illustrated in the section view ofFIG. 19. Guard 69 is similar to the guard described above except thatone edge wall 70 of the guard 69 is provided with a longitudinal recess71 which is best illustrated in the section view of FIG. 18. Thus, guard69 is firmly held in recess 66 by having rib 68 trapped inside recess71. This means that the guard 69 cannot be inadvertently lifted out ofthe recess 66 in handle 65.

FIGS. 22-25 illustrate another way to prevent the guard from beingremoved from the handle. Again, this improvement requires modificationto the guard and to the handle. Guard 72 (see FIG. 23) is provided withan engagement means in the form of the safety catch which prevents guard72 from being retracted too far rearwardly and thus possibly able to beretracted out of the recess 74 in handle 73. Specifically, the front ofguard 72 is provided with a peg 75 best illustrated in FIG. 24. Peg 75is formed integrally with guard 72 and extends at right angles from thefront end of guard 72 such that peg 75 points towards handle 73 (inuse). Peg 75 will abut against a stop 76 formed in handle 73 when guard72 is fully retracted. Thus, guard 72 cannot be retracted too far as peg75 will prevent this from occurring.

FIGS. 26-29 illustrate another improvement which is to provide apositive temporary locking of the guard when in the forward and theretracted position. In the embodiment, the arrangement is such toprovide an audible “click” sound in the forward position and theretracted position such that the surgeon can be more confident of theguard being fully retracted or extended.

In the embodiment, this is achieved by providing at least one projectionwhich can releasably engage with at least one recess when the guard isin the forward position and the retracted position. Specifically, theprojection (locking bump 80) is provided of the handle 81 and the recess(location hole 82 is provided on guard 83. A ramp 84 is providedadjacent a forward part of the scalpel to lift the guard out of lockingbump 80 as the guard is being retracted. Similarly, a ramp 85 isprovided to lifted guard out of locking bump 80 when the guard is beingextended.

Referring to FIGS. 30 and 31, there is illustrated a variation to thescalpel. The scalpel has a handle 90 containing a forwardly extendingfinger or nose portion 91 to which the scalpel blade is attached. Thescalpel blade 92 is protected by the guard 93, the guard beingsubstantially as described above. The scalpel blade 92 and guard 93 areattached to the forwardly extending finger 91 in the manner describedabove. This particular variation allows the guard 93 to be fullyretracted and fully extended and provides an audible “click” when theguard is in the fully retracted position and the extended position. Thisallows the surgeon to retract the guard until the audible click isheard. When the guard is “clicked” into the retracted position, there islittle likelihood of the guard being inadvertently moved to the forwardposition for the reasons described below.

Guard 93 is made of clear plastic material and contains a smallextending button or projection 95 which is illustrated in FIG. 30. Thebutton or projection is formed integrally with the guard 93 and iscylindrical having a diameter of approximately 1 mm and projecting (awayfrom blade 92) by distance of about 1 mm. This button can be called thefront button.

Guard 93 is also provided with a rear button 96 which has a size andshape similar to that of the front button 95, and rear button 96 isillustrated in FIG. 31.

The handle 90 is formed of plastic material and contains a recess 97 toaccommodate guard 93 as guard 93 is retracted to expose blade 92. Recess97 is formed with a rear hole 98 and a front hole 99 (both illustratedin FIG. 31). Each hole 98, 99 is designed to accommodate the respectivefront button 95 and rear button 96. Specifically, rear hole 98accommodates rear button 96 and front hole 99 accommodates front button95. As a button overlies a hole, the button is pressed into the hole andgives an audible “click” sound. Specifically, as guard 93 is retractedto expose blade 92, in the fully retracted position, the front button 95passes into the front hole 99 at the same time that the rear button 96passes into rear hole 98.

As guard 93 is retracted to expose blade 92, front button 95 at somestage will strike the front wall portion 102 of handle 90 (see FIG. 30).At this stage, the guard is sufficiently retracted to expose blade 92. Asurgeon can either elect to keep the guard retracted in this manner andcan easily push the guard back over the front of blade 92 to protect theblade when not required. However, when in this retracted position, thesurgeon can also pull the guard back to a greater extent which willcause front button 95 to ride over front wall portion 102 and intoengagement with front hole 99. In this fully retracted position, theguard is not easily (and therefore cannot inadvertently) move back tothe blade protecting position.

Recess 97 contains a central elongate rib 100 and the rear of guard 93is provided with a channel to enable the guard to slide along rib 100.The sidewalls 101 of recess 97 also guide the guard into a smoothretracting direction.

FIGS. 30 to 37 illustrate the attachment and removal of the protectedscalpel blade to the handle. In FIG. 32, the blade 92 is mounted ontothe handle by inserting the handle tip (finger) 91 into the blade slotas described above. The arrangement is then pulled back onto the handleuntil an audible click is heard when the arrangement is pulled back ontothe handle to a sufficient amount. At this stage, the blade is not yetexposed. The safety tab 61 (see FIG. 33 and 34) is bent back and brokenoff. Only when the safety tab has been removed is the guard 69 pulledback (see FIG. 35) to expose blade 92. Typically, the person attachingthe blade will have a “dominant” hand and a “free” hand. The guard isfirst attached to the handle using both hands (see FIG. 32). Thedominant hand holds the handle and the free hand must be removed fromthe vicinity of the blade to prevent being cut. The safety tab 61 isdesigned to force the free hand to grip and remove the tab to preventthe free hand from manipulating the guard, and also ensures that thefree hand is moved away from the blade by the downward motion of thefree hand when tab 61 is removed (see FIG. 34) Guard 69 can be pulledback until an audible “click” is heard which means that the guard hasbeen fully retracted to expose the blade. The guard can be pushedforwardly (see FIG. 36) to cover blade 92 and this can be donerepeatedly especially when the scalpel is passed from one person toanother person. To dispose of the blade and guard, the guard is pushedforwardly and is gently scooped to remove the blade from the handle. Theblade containing the guard (the blade being covered by the guard andtherefore preventing a sharps hazard) can then be discarded into asharps container 110 (see FIG. 37).

It should be appreciated that various other changes and modificationscan be made to the embodiment described without departing from thespirit and scope of the invention as claimed.

1. A safety scalpel blade assembly adapted for attachment to a handle ofthe type which has a blade carrier in the form of a finger, the assemblycomprising a scalpel blade which can be of conventional manufacture, thescalpel blade having a slot to allow the blade to be attached to theblade carrier on the handle, and a guard which extends at least aboutthe cutting edge of the blade, the guard having attachment means to lockthe blade to the guard as the assembly is being attached to the handleand which releases the blade from the guard when the blade is attachedto the blade carrier on the handle, and a removable tab on the guardhaving a portion which can be gripped by a person.
 2. The assembly asclaimed in claim 1, wherein the removable tab has a head portion and atail portion, the head portion extending forwardly of the bladeassembly, and the tail portion extending at least partially into a slotwhich is present in the guard.
 3. The assembly as claimed in claim 2,wherein the removable tab is attached to the guard via at least onebreakable portion.
 4. The assembly as claimed in claim 3, wherein thebreakable portion comprises a first breakable portion (a first neck) anda second breakable portion (a second neck).
 5. The assembly as claimedin claim 4, wherein the first breakable portion is closer to the headportion of the removable tab and breaks more easily than the secondbreakable portion.
 6. The assembly as claimed in claim 2, comprisinganti-lift means to reduce the ability of the blade guard from liftingrelative to the handle.
 7. The assembly as claimed in claim 6, whereinthe anti-lift means comprises an engagement means on the handle whichengages the guard.
 8. The assembly as claimed in claim 7, wherein theengagement means comprises an elongated rib or rail in the handle, and acorresponding groove or slot in the guard (or vice versa) such that theguard can slide between the forward and the retracted position but isheld against being lifted by the engagement of the rib or rail in thegroove or slot.
 9. The assembly as claimed in claim 2 comprising asafety catch to prevent excessive retraction of the guard, the safetycatch being positioned on a forward part of the guard and comprising aprojection.
 10. The assembly as claimed in claim 2 comprising a locationmeans to positively locate the guard in the extended position and theretracted position.
 11. The assembly as claimed in claim 10, wherein thelocation means comprises at least one projection which releasablyengages in at least one recess when the guard is in the extendedposition and the retracted position.
 12. A safety scalpel assemblycomprising a scalpel blade attached to a handle of the type which has ablade carrier in the form of a finger, the assembly comprising a scalpelblade having a slot to allow the blade to be attached to the bladecarrier on the handle, and a guard which extends at least about thecutting edge of the blade, the guard having attachment means to lock theblade to the guard as the assembly is being attached to the handle andwhich releases the blade from the guard when the blade is attached tothe blade carrier on the handle, and anti-lift means to reduce the bladeguard from lifting relative to the handle, the anti-lift meanscomprising an elongate recess in the blade guard which is adapted toengage a rib on the handle.
 13. A safety scalpel assembly comprising ascalpel blade attached to a handle of the type which has a blade carrierin the form of a finger, the assembly comprising a scalpel blade whichcan be of conventional manufacture, the scalpel blade having a slot toallow the blade to be attached to the blade carrier on the handle, and aguard which extends at least about the cutting edge of the blade, theguard having attachment means to lock the blade to the guard as theassembly is being attached to the handle and which releases the bladefrom the guard when the blade is attached to the blade carrier on thehandle, and a safety catch to prevent excessive retraction of the guard,the safety catch being positioned on a forward part of the guard andcomprising a projection.
 14. A safety scalpel assembly comprising ascalpel blade attached to a handle of the type which has a blade carrierin the form of a finger, the assembly comprising a scalpel blade whichcan be of conventional manufacture, the scalpel blade having a slot toallow the blade to be attached to the blade carrier on the handle, and aguard which extends at least about the cutting edge of the blade, theguard having attachment means to lock the blade to the guard as theassembly is being attached to the handle and which releases the bladefrom the guard when the blade is attached to the blade carrier on thehandle, and a location means to positively locate the guard in theextended position and the retracted position.